A microwave assisted magnetic recording writer is disclosed with an octagonal write pole having a top portion including a trailing edge that is self aligned to a spin transfer oscillator (STO). Leading and trailing edges are connected by two sidewalls each having three sections. A first section on each side is coplanar with the STO sidewalls and is connected to a sloped second section at a first corner. Each second section is connected to a third section at a second corner where the distance between second corners is greater than the distance between first corners. A method of forming the writer begins with a trapezoidal shaped write pole in an insulation layer. Two ion beam etch (IBE) steps are used to shape top and middle portions of the write pole and narrow the pole width to